How to achieve cake crust material?
You could try something like this.

What I did was combine a Musgrave and a Noise texture and used that as a mix factor for the &quot;Cake colors&quot;. I then took a lightened (softened) version of this mix and used that as a Bump Map of sorts. I also took the normal values from the Bump map, and the color data from the Noise Texture to provide the values for an Ambient Occlusion Node which I then colored dark brown and mixed with the original &quot;cake color&quot; to make the &quot;darkened baked bits&quot;.
Lastly, I isolated the Z vector of a Gradient Texture (so it would lay flat) and &quot;shaped&quot; it with a ColorRamp to make a &quot;top cap&quot; mask which I would then use as a mix factor to apply the whites of yet another Noise Texture to the Cake by using a MixRGB node set to lighten. This makes the &quot;icing sugar&quot; on top.